No, it doesn't.
With either Proportional option, we'd have a very similar number of representatives as what we have now.
Currently we have 27 MLAs. With Mixed-Member Proportional (MMP) the Island would have 18 district MLAs and 9 province-wide MLAs, totalling 27. With Dual-Member Proportional (DMP) we'd have 13 or 14 districts with 2 representatives for each district - for 26 or 28 MLAs in total.
Since the number of representative would likely not change drastically, the overall cost to pay representatives would not be substantially different.
To put things in perspective: the budget for PEI's Legislature is only about 0.5% of the province's annual budget for things like healthcare, education and infrastructure. The provincial legislature controls spending for approximately $1.7 BILLION of our taxes. With proportional representation, we have more transparency and better oversight over how that money is spent. That's where the real savings happen!